Testing Duct Smoke

I've always just used the magnetic test switch to make sure the unit shuts down. The duct detectors come with big 1" x 1" magnets for that purpose.

Remove the cover. Remove the detector. Pull the sample tubes and ensure none of the orifices are plugged with debris. Make sure they're oriented correctly as you pull them (the inlet tube should have the holes in the tube facing the towards the high pressure side, the outlet tube should be facing the "lower pressure" side. Ensure there's flow through the sensing chamber. Pull the cover off the smoke. Ensure the chamber isn't clogged with dust or debris. If it is, clean it with isopropryl alchohol (99% pure) and a soft bristle brush (I like the camel hair shaving brushes). Use high quality "Dust Buster" canned air to dry it. We always use canned smoke to test the detector. If it's an ionization type, I'd recommend replacing it after ten years. Whether the customer goes for that is up to them. On the older Edwards duct detectors, they're no longer manufacturing the actual unit, and you'll have to replace the entire assembly (which can be a real pain). There are usually relays which the detector trips (that shut down the fans). Make sure the voltages on the relays are within the manufacturer's specs. I've seen a number of installations where they aren't and an additional relay (or contactor) is required. Re-assemble everything and place your inspection sticker with the service date on the cover so it's visible to the AHJ.

Good luck!!

Regards, Frank (no, not *that* Frank, the "other one")

WHAT!?! Clean a smoke with alcohol? Heh, heh, heh... :^)

I don't think "alcohol" was the issue (in another thread). It was the cleaning "method" (swabs as opposed to brush). I get better results with the latter.

I've used both and found that swabs work just as well. I do not use Q-Tip brand swabs. Like some here, those are too loosely wrapped and will occasionally leave fibers though none leave a "film" as the other poster claimed. The other poster did indeed object to alcohol though I notice no such objection when you said the same thing. Can we say, "disingenuous?"

brand swabs. Like some here, those are too loosely

other poster claimed. The other poster did indeed

thing. Can we say, "disingenuous?"

No, but we can say you're a f****ng asshole though. Read it again, you jerk.

If you had any experience at all, you'd know that if you try to clean thick dust or drywall dust from a smoke detector chamber with simply alcohol and a swab, you'll spend too much time trying to clean the film from the chamber. By using a brush dipped in alcohol, you can "scrub" the debris from the chamber with the solvent action of the alcohol and then rinse under the flow of water from a sink, which actually removes the debris and alcohol rather than letting the alcohol evaporate, leaving a film. Since alcohol has an affinity for water, the combination of alcohol and water, during rinsing, assures that there is no visible or invisible film remaining, that would cause the chamber to catch more dust and dirty up all the sooner. Air dry or blow dry. I use a round, stiff, 2 inch paint brush which scrubs the chamber cleaner than any Q-tip and doesn't leave the little cotten strands from the Q-tip behind either.

But .... since you only know what you read in the instructions and from what you hear from people with field experience and have never actually installed anything yourself, it's understandable that you wouldn't know what it's like to clean a detector.

To any who are interested, you might try giving this method a test run.

Years ago, when doing commercial work I actually timed the period between smoke detector cleanings on a multitude of jobs (over 100). When I started cleaning them using the above method, times between (forced) cleanings got longer ( by many months, it varied from job to job) and there seemed to be less debris when cleanings were done on a yearly scheduled basis. I kept track for about 6 years.

And .... Oh yeh Bass...... arent' you dead yet? You're really dragging this out .... ya know?

Heh .... five years ...... yeah sure...........

If there's a lot of dust you first wipe it with a lint free cloth or a brush. Otherwise alcohol swabs alone work perfectly.

[sarcasm] Yeah, right. Rinse your smokes in the sink. After that be sure to put the keypads in the dishwasher. [/sarcasm]

have you seen his ears? NO, well you're fortunate. he uses those swabs frrom the zoo that they use on dumbo the elephant's ears. ;)

Roll of Viva towles on a broom handle?